This invention relates to a high pressure gas cooler of the type having at least two cylindrical pressure containment vessels disposed in series with respect to gas flow and, more particularly to an apparatus for collecting the fluid discharging from heat exchange tubes lining the pressure containment vessel and directing that fluid to a fluid collection drum disposed outside of the pressure vessel without penetrating through the pressure vessel wall.
It is often necessary to cool a high pressure hot gas by passing it in heat exchange relationship with a cooling fluid such as water or steam without the two fluids coming into contact. This is frequently done by submerging heat exchange surface in one or more pressure containment vessels through which the gas will pass and passing the cooling fluid through the heat exchange surface such that the fluid and gas pass along opposite sides of the heating surface and heat is transferred from the gas to the cooling fluid across the heating surface. In many cases, the gas to be cooled will be at a pressure as high as 1500 psi and at a temperature in excess of 3000.degree. F. Accordingly, the pressure containment vessels will be relatively thick walled. Consequently, severe temperature gradients will exist through the pressure vessel walls because of the substantial temperature differential between the ambient atmosphere outside of the shell and the hot gas passing through the shell, unless the pressure vessel is cooled to a uniform temperature.
A common method of cooling a pressure vessel wall is to pass a cooling fluid such as water through a plurality of heat transfer tubes lining the interior of the pressure vessel wall. As the cooling fluid flows through the wall, the fluid will absorb the radiative heat from the hot gas thereby protecting the pressure vessel wall from exposure to the hot gas and evaporate to form steam so that the pressure vessel wall is maintained uniformly along its length at the saturation temperature. By maintaining the interior surface of the pressure vessel wall at the saturation temperature, the temperature gradient through the pressure vessel wall is reduced to a level well within the design tolerance of the wall.
A problem associated with cooling the pressure vessel wall in this manner is that the cooling fluid passing through the heat transfer tubes lining the vessel wall must be directed to a collection drum outside of the pressure vessel. Consequently, a plurality of penetrations through the pressure vessel must be provided in order that the cooling fluid may be directed to the collection drum. Stresses within the pressure vessel wall tend to concentrate at these penetrations and over a period of time can result in failure of the pressure vessel wall. Further, nozzles and thermal sleeves of elaborate construction must be provided at these pentrations in order to accommodate differential thermal expansion between the vessel wall and the tubes penetrating therethrough.
Accordingly, it is the object of this invention to provide a ring header of unique design which allows the cooling fluid passing through the heat transfer tubes lining the pressure vessel to be collected and directed to a collection drum disposed outside of the pressure vessel without a single penetration of the pressure vessel wall.